Fluid Mechanics

Fluid Mechanics is a core subject in Mechanical / Civil / Chemical Engineering that deals with the behavior of fluids (liquids and gases) at rest and in motion. It explains how fluids flow, exert forces, and interact with solid boundaries.

• Objectives of Fluid Mechanics
  • Understand basic properties of fluids
  • Analyze fluid behavior at rest (statics) and in motion (dynamics)
  • Apply fluid laws in engineering systems like pipes, pumps, turbines
  • Develop problem-solving skills for real-life fluid applications

What is a Fluid?

A fluid is a substance that can flow and cannot resist shear force.
Examples:

• Liquids → water, oil
• Gases → air, steam

Main Parts of Fluid Mechanics

1. Fluid Statics (Fluid at Rest):- This deals with fluids not moving.
   • Pressure in water tanks
   • Pressure increases with depth
   • Hydraulic jack & press
     • Example: Water pressure at the bottom of a dam is more than at the top.
2. Fluid Kinematics (Motion without force):- This studies how fluids move, not why.
   • Types of flow (laminar, turbulent)
   • Velocity of fluid
   • Streamlines
     • Example: Smooth flow of water in a small pipe.
3. Fluid Dynamics (Motion with force):- This explains why fluids move by considering forces.
   • Pressure energy
   • Velocity energy
   • Bernoulli’s theorem
     • Example: Airplane lift, water flowing faster in narrow pipes.

• Important Fluid Properties
  • Density – How heavy fluid is
  • Viscosity – Thickness of fluid (oil > water)
  • Pressure – Force applied by fluid
  • Surface tension – Water droplets formation